1. Field of the Invention
The present invention relates to satellite navigation technology, and more particularly, to a navigator that can reduce current consumption in a gap of an orbiting GPS satellite signal and a method for reducing the current consumption of navigator.
2. Description of the Related Art
In general, a Global Positioning System (GPS) is a satellite navigation system used for determining a GPS navigator's precise location using a GPS satellite signal from a GPS satellite, and is used in various fields, such in vehicles, vessels, and as navigation systems for airplanes, etc.
The GPS navigator receives an orbiting GPS satellite signal and calculates its current location. As well, the navigator must successively track the orbiting GPS satellite signal to perform a navigation mode where its current location is updated. Here, tracking the orbiting GPS satellite signal refers to a process in which the GPS navigator detects the GPS satellite signal to successively receive it.
After that, the GPS navigator extracts GPS data from the orbiting GPS satellite signal that was tracked and then calculates a pseudo distance using the extracted GPS data, thereby calculating its current location.
The following is a description of operations of the conventional GPS navigator with reference to FIG. 1.
As shown in FIG. 1, when a GPS navigator inputs power and thus drives the GPS signal-receiving unit, in Step S101, the GPS navigator tracks an orbiting GPS satellite signal using n channels described in following Table 1, in Step S103. Here, the n channels are allocated to the GPS navigator to track the GPS satellite signal.
TABLE 1
After tracking, the GPS navigator measures the tracked orbiting GPS satellite signal strength, in Step S105.
Next, the GPS navigator makes a determination as to whether the measured signal strength exceeds a previously allocated critical value, in Step S107.
When the determination of Step S107 is negative, or the signal strength is less than the critical value, the procedure is returned to Step S103 to perform the following Steps thereof.
On the other hand, when the determination of Step S107 is positive, or the signal strength is greater than the critical value, the GPS navigator tracks the orbiting GPS satellite signal, in Step S109.
After that, the GPS navigator operates in a navigation mode where its current location is calculated based on the tracked orbiting GPS satellite signal, in Step S111.
Then, the GPS navigator determines as to whether a navigation termination request signal is input, in Step S113.
When the request signal is input in Step S113, the GPS navigator terminates its navigation operation. Otherwise, the procedure is returned to Step S103 and then the following Steps thereof are performed as described above.
As described above, the conventional GPS navigator performs signal tracking using the entire allocated channels at any location, even in a gap (for example, inside a building or tunnel) where it should not have performed such a tracking. Therefore, the conventional GPS navigator wastes current.